He was generally in evening dress - black pantaloons (tight) and a white waistcoat, with Blue Ribbon and Garter.
Many of the dresses listed under the Evening Dress category on the Cache website would be well suited for a prom dress as well.
For night weddings, black tie-only events, and most indoor weddings, an evening dress is more appropriate.
Based on many flower girl dress styles, this evening dress option is both beautiful and classy, and perfectly appropriate for young girls.
For the holiday season, a fancy evening dress might be needed.